Computer Science and Engineeringhttp://repository.iitgn.ac.in/handle/123456789/427
Mon, 19 Mar 2018 14:51:03 GMT2018-03-19T14:51:03ZOn structural parameterizations of firefightinghttp://repository.iitgn.ac.in/handle/123456789/3528
On structural parameterizations of firefighting
Das, Bireswar; Enduri, Murali Krishna; Misra, Neeldhara; Reddy, I. Vinod
The Firefighting problem is defined as follows. At time Open image in new window , a fire breaks out at a vertex of a graph. At each time step Open image in new window , a firefighter permanently defends (protects) an unburned vertex, and the fire then spread to all undefended neighbors from the vertices on fire. This process stops when the fire cannot spread anymore. The goal is to find a sequence of vertices for the firefighter that maximizes the number of saved (non burned) vertices. The Firefighting problem turns out to be NP-hard even when restricted to bipartite graphs or trees of maximum degree three. We study the parameterized complexity of the Firefighting problem for various structural parameterizations. All our parameters measure the distance to a graph class (in terms of vertex deletion) on which the Firefighting problem admits a polynomial time algorithm. Specifically, for a graph class Open image in new window and a graph Open image in new window , a vertex subset Open image in new window is called a modulator to Open image in new window if Open image in new window belongs to Open image in new window . The parameters we consider are the sizes of modulators to graph classes such as threshold graphs, bounded diameter graphs, disjoint unions of stars, and split graphs.To begin with, we show that the problem is W[1]-hard when parameterized by the size of a modulator to diameter at most two graphs and split graphs. In contrast to the above intractability results, we show that Firefighting is fixed parameter tractable (FPT) when parameterized by the size of a modulator to threshold graphs and disjoint unions of stars, which are subclasses of diameter at most two graphs. We further investigate the kernelization complexity of these problems to find that Firefighting admits a polynomial kernel when parameterized by the size of a modulator to a clique, while it is unlikely to admit a polynomial kernel when parameterized by the size of a modulator to a disjoint union of stars.
Thu, 15 Feb 2018 00:00:00 GMThttp://repository.iitgn.ac.in/handle/123456789/35282018-02-15T00:00:00ZOn structural parameterizations of happy coloring, empire coloring and boxicity",http://repository.iitgn.ac.in/handle/123456789/3494
On structural parameterizations of happy coloring, empire coloring and boxicity",
Choudhari, Jayesh; Reddy, I. Vinod
Sat, 03 Mar 2018 00:00:00 GMThttp://repository.iitgn.ac.in/handle/123456789/34942018-03-03T00:00:00ZDocker container scheduler for I/O intensive applications running on NVMe SSDshttp://repository.iitgn.ac.in/handle/123456789/3473
Docker container scheduler for I/O intensive applications running on NVMe SSDs
Bhimani, Janki; Yang, Zhengyu; Mi, Ningfang; Yang, Jingpei; Xu, Qiumin; Awasthi, Manu; Pandurangan, Rajinikanth; Balakrishnan, Vijay
By using fast back-end storage, performance benefits of a lightweight container platform can be leveraged with quick I/O response. Nevertheless, the performance of simultaneously executing multiple instances of same or different applications may vary significantly with the number of containers. The performance may also vary with the nature of applications because different applications can exhibit different nature on SSDs in terms of I/O types (read/write), I/O access pattern (random/sequential), I/O size, etc. Therefore, this paper aims to investigate and analyze the performance characterization of both homogeneous and heterogeneous mixtures of I/O intensive containerized applications, operating with high performance NVMe SSDs and derive novel design guidelines for achieving an optimal and fair operation of the both homogeneous and heterogeneous mixtures. By leveraging these design guidelines, we further develop a new docker controller for scheduling workload containers of different types of applications. Our controller decides the optimal batches of simultaneously operating containers in order to minimize total execution time and maximize resource utilization. Meanwhile, our controller also strives to balance the throughput among all simultaneously running applications. We develop this new docker controller by solving an optimization problem using five different optimization solvers. We conduct our experiments in a platform of multiple docker containers operating on an array of three enterprise NVMe drives. We further evaluate our controller using different applications of diverse I/O behaviors and compare it with simultaneous operation of containers without the controller. Our evaluation results show that our new docker workload controller helps speed-up the overall execution of multiple applications on SSDs.
Thu, 01 Feb 2018 00:00:00 GMThttp://repository.iitgn.ac.in/handle/123456789/34732018-02-01T00:00:00ZAn evaluation of multi-probe locality sensitive hashing for computing similarities over web-scale query logshttp://repository.iitgn.ac.in/handle/123456789/3445
An evaluation of multi-probe locality sensitive hashing for computing similarities over web-scale query logs
Cormode, Graham; Dasgupta, Anirban; Goyal, Amit; Lee, Chi Hoon
Many modern applications of AI such as web search, mobile browsing, image processing, and natural language processing rely on finding similar items from a large database of complex objects. Due to the very large scale of data involved (e.g., users’ queries from commercial search engines), computing such near or nearest neighbors is a non-trivial task, as the computational cost grows significantly with the number of items. To address this challenge, we adopt Locality Sensitive Hashing (a.k.a, LSH) methods and evaluate four variants in a distributed computing environment (specifically, Hadoop). We identify several optimizations which improve performance, suitable for deployment in very large scale settings. The experimental results demonstrate our variants of LSH achieve the robust performance with better recall compared with “vanilla” LSH, even when using the same amount of space.
Mon, 01 Jan 2018 00:00:00 GMThttp://repository.iitgn.ac.in/handle/123456789/34452018-01-01T00:00:00Z